Roller skiing is a well-known training exercise used by cross-country skiers/athletes to enable effective and sport-specific training during all seasons where the athlete may not be able to train on snow.
A typical roller ski includes a central body having both forward and rear wheels that generally have a size that provides a comfortable rolling movement over typical pavement and that does not elevate the skier substantially higher than the height of a typical cross-country ski. In addition, the typical roller ski is designed to have a length that is not unwieldy for use on narrow paved trails or having a weight that is substantially different than a typical snow ski. Roller skis also permit standard cross-country ski bindings to be configured to the upper surface of the main body of the roller ski thereby allowing the athlete to attach the roller ski to a standard cross-country ski boot. Roller skis are designed for both skating and classical techniques of cross-country skiing.
While there are many designs of roller skis, one problem associated with roller skis is the severe vibrations that can be imparted to the athlete during use. In particular, rough pavement and/or high speed can impart significant vibrations that are both uncomfortable and that can lead to control/safety issues during use. That is, at high speed as vibrations are transmitted through to an athlete's legs, a numbing effect can occur that can affect the ability of the athlete to control the roller skis. As a roller skier can attain significant speeds over pavement and where crashes and significant injury can occur, reducing the numbing effect can substantially improve the safety of roller skis.
As a result of these limitations, many athletes simply do not train as effectively as they might due to the perception of risk and/or the discomfort of using roller skis on rough pavement or at higher speeds.
Accordingly, there has been a need for a roller ski system that incorporates a suspension system to minimize or otherwise reduce the vibrations within roller skis during use.
Further still, roller skiers will range in weight from as light as approximately 90 pounds to over 200 pounds. With snow skis, the differences in height and weight between skiers can be accommodated by a wide range of ski lengths and ski stiffness that can be selected to ensure a proper fit for a particular athlete. That is, shorter skiers will generally purchase shorter skis and taller skiers will purchase longer skis. The relative stiffness of a ski will also be selected to match the weight of the skier.
The stiffness of the ski ensures that for a given weight of skier that the ski contacts the snow properly during each phase of a ski stride. For example, during the push phase of a skate-skiing stride, the stiffness of the ski should be sufficient that for a given skiers weight that the inside edge of the ski is fully compressed against the snow surface as the maximum pressure being applied by the skier is reached. That is, as the skier fully loads one leg, the ski should deflect such that at the point that maximum pressure is being applied to that ski, the edge of the ski is in full contact with the snow. As such, it is also important that the ski is not too soft and that the time at which the edge of the ski contacts the snow does not occur too early in the cycle as this will increase friction between the ski and the snow and also reduce the amount of energy that may be returned as the glide phase of the ski stride is commenced.
That is, as the glide phase commences and the skier is transferring their weight to the opposite ski, the compressed ski returns energy to the skier as the energy in the compressed ski is released. Importantly, the camber of a ski stores this energy throughout the length of the ski wherein the ski is compressed evenly and thereby returns the energy evenly as the ski is transitioned to the glide phase.
Thus, there has also been a need for a roller ski to more accurately replicate the actions of a ski on snow within a roller ski such that the roller ski compresses and returns energy in the same way that a snow ski does.
Further still, there has been a need for classical technique roller skis that more accurately simulate the action of classical technique and more particularly a roller ski that has a pressure sensitive ratchet system that requires that a roller skier properly transfer their weight between skis to effect engagement of the ratchet system to prevent rearward motion of the ski.
A review of the prior reveals that while various roller ski designs have been proposed in the past, there has been a need for improved designs that realize the above objectives more effectively. One example of a classic technique roller ski is found in US Publication 2008/0030014.